Communication between a calling party (source) and a called party (destination) may be established over a communications network. Such a communications network may use source routing protocols in order to establish connections over which such communication can occur. Communication networks that support source routing protocols typically include a number of individual switches through which calls are routed. A call set-up message is sent along a path between the source and the destination through a number of intervening switches in order to establish the call.
Signaling protocols can encounter congestion in the control plane used to carry such set-up messages. The control plane congestion can be the result of a number of different factors, including an overabundance of signaling traffic such as call set-up messages and/or control plane datagram messages, device speed mismatches within the communication network, or over-utilization of particular nodes or switches within the network.
In prior art systems, when a set-up message encounters a congested element or link within the network, no notification of such congestion is returned to the source node that issued the connection set-up message. As such, the source node may try the same path or a similar path for subsequent connection set-up. Such subsequent connection set-up messages may then encounter the same congestion encountered by the initial connection set-up message and may in fact compound the congestion. Repeated attempts to route connection set-up messages through congested portions of the network often result in unacceptable call set-up delays or in calls not being established at all.
Therefore, a need exists for a method and apparatus that allows for avoidance of congestion in source routed signaling protocol networks.